Method of making hollow bars



Feb. 15 1927.

T. B. WHEELWRIIGHT METHOD OF MAKING HOLLOW BARS Filed May 12, 1926 gum#14304;

Patented Feb. 15, 1921. a

rnoms s. wnnnnwnrenr, or nocxnnan srnmes, v'meirmnssreuonro on) men &STEEL wonxs, or RICHMOND, vmemm. A oonroaa'rron or noimuon 1,618,142UNITED STATES; PATENT n METHOD OF M AKIN G HOLLOW BARS.

Application filed May 12, 1926. Serial No. 108,303.

This invention relates to the manufacture of rolled or drawn hollowarticles; and is especiall applicable for making stay-bolt iron, alt ougit may be applied to many other pur oses.

Hereto ore long hollow bars have been made by takinga solid billet .anddrilling it from end to end, and then rolling down to size. Stay-boltiron has usually. been;

rolled; then cut to length; and then drilled.

This is a costly operation because of the loss of metal, and the laborincident to the drilling. There has, also been difiiculty in' producinga itslength. I

My invention consists essentially in the economical production of hollowbars by building up a hollow fagot by arranging rods or bars around ahollow metal core, heating the built-up fagot to a welding. and rollingtemperature, rolling the heated fagot down to the required size andsection, at the bar with a straight hole through same time. preservingthe desired direction.

of the hole through the axis of the bar.

A fagot may be built up of plates, flat bars, and even of scrap; but theresulting bar would not be suitable for the manufac-' ture of sta bolts,in which great strength and reliab' it are essential. I have found thatby buil ing upmy fagot of bars of.

small section, and themselves of good quality, and then by rolling downby steps to the required size, I obtain a finished bar of unusualstrength and soundness. I r

I-u'se my roceSs particularly for the production of iiollow stayboltiron, from end to end of which runs a tell-tale hole; but I do not limitmy process tothe production of hollow iron bars, for by the same processI can produce hollow bars of ther weldable materials such as lowc'arbonsteel.

In describing my process I use, for theenveloping cure them sake ofbrevity. and simplicity.- terms appli- Re ferring totheaccompanymgdrawings which form a part of this specification; Figure 1 shows in'endelevation'a method of building upa fagot. v Figures 2, 3, and 4 showother methods of building up the fagot.

f Figure 5 shows a fagot in side elevation.- Figure 6 shows a'detail ofthe rolls. 3 Fi re 7- shows in detail the manner in whic the bore of thefinished bar is cleaned.

"t e first and n qa -ry g o t my p' entian I P 4? a fagot by assemblingiron bars or rodsaround a.hollow central core, as shown 1n Figures 1, 2,and 3. In Figure 1 the fagot H is formed by setting up a wrought iron ppe A; and concentrically with this pipe I set up another second andsmaller wrought iron pipe B -of the same length. Thespace be tween thesepipes I then pack with iron bars or rods 0, with the axes of the barslying approximately parallel to the axes of the two pipes. The sizes ofthe two pipes will depend very much upon the length of stay-bolt.

iron which it is desired to roll; but for usual lengths the size of theouter pipe A may be from 4-lllChGS to.6 inches, andthe size of thesmallerpipe may be fr'onf 1. inch to 1% inches. The length of the twopifies ispreffrably 30 inches; though it may ,ess

Another way of making this fagot is e more 01* shown in Figure 2. Itisnot always desir- 'able to use a piece ofcommercial wrought packed intothe space between the semi-circular plates D and hollow iron core B.

-E. The wrought iron rods or. bars are theng In Figure 3 I show anothermethod of I forming the fagot. In this case I set u in a form flat barsF of suitable width to 'orminsection an octagon or a hexagon, or otherpolygonal figure, of the desired size. the hollowwrought ter; then I ackthe space between it and the surrounding plates with, the wrought iron"rods or bars G; and then I wrap the plates aroundwith wire to se--moved from the form.

The fa'got may be built-up 1n other ways;

for instance, by suitably arranging therods -orbars around the hollowmetal core, and

.then wrapping the bundle tightly with wire,

inafter; andI then thrust the fagot into a ,heati furnace, and raise, toa welding and rollmg' temperature. I then remove I.set iron core B n the.cen-

in vlace. before the whole is reasinFi re4., The fa got built up I fillthe core w th refractory material, as explained herethe fagot, and sendit immediately throng:

su c eding p c i th It has been found that if a hollow billet 01 fagotis rolled through succeeding circular passes, it will turn and twist, somuch so that the hole through the center of the bar will become verymuch distorted, and may even atplaces become closed. I have found that"I can prevent the turning of the bar, as it is reduced by the rolls, byusing rolls having passes octagonal or hexagonal in shape,

in other words polygonal, rather than one sided, such as the circularpass. In the drawings I have shown rolls having octagonal passes II. Itshould be noted that in feeding the bar J into a pass I do not turn thebar so that its anglesv come in contact with the flats of the pass; butI feed it in with its flats in approximately the same planes as theflats of the pass. Bythis manher of feeding, the bar is less liable todistortion; and it is more readily reduced to iron.

-During the process of heating and rolling, the center hollow core, andthe rods, and the outer envelope become welded together; and there isproduced a long bar of accurate size, perforated from end to end with asmall hole. In the case of bar rolled for stay-bolts this hole isusually to of an inch in diameter.

In order to prevent the collapse of the inher metal core during theheating or rolling, I pack the said core with a refractory material, G,preferably without any binding" material, except that with somerefractories I may use a small quantity at each end to hold therefractory material in place during gthe heating and the first part ofthe rolli gfer the fagot. 1 My usual practice is to plug the ends of themetal core after filling itwith the refractor materials. For thef-refractory materiaL may use any sub: stance which will not fuse at arolling temperature for example, silica sand, soap.-

stone, graphite, carborundum sand, zircon sand, electricallysinteredalumina, or magne'sla, or any other granular or powderedrefractory material the fusing point of which is higher than thetemperature of the metal when heated for rollin The removal of 'therefractory material from the finished bar-has heretofore been adifficult operation, and a costly one. I have found a simple andinexpensive method of removing therfractory core. I" mount the bar in alathe or other machine b which it may be revolved on its a xis'gaandmetal tube, approximately aslong as the bar, and of a size small enoughto enter the core-hole'easily, to a source of supply of compressed air.I start the bar '(see M in Figure 7) revolving more or less rapidly,.

and I then introduce the free end of the metal tube, N, into the end ofthe core-hole; and turn on the compressed air. Theobject of rotating thebar is to produce a relative rotary motion between the core and the jetof compressed air. ,The jet of air then acts upon the core in somewhatthe same way as.

connect a suitable rests. The pressure of air I prefer to use isapproximately '100 lbs. per square inch; though other pressures may beused. This pressure is elfectivefor the removal of the core; and it isalso a pressure commonly available in industrial plants. As the hollowtube is-inserted into the end .of the corehole the refractory isloosened by the rapidly flowing air, but not necessarily by contact withthe end of the tube; and the loosened refractory is expelled rapidlyfrom the core backward around the tube. By this method I am able toremove the core cleanly and rapidly, and at a very small cost.

I claim:

1. The method of making hollow metal bars, which comprises bundlingweldable metal around a hollow core also of weldable metal to form afagot; packing the hollow core withrefractory material; heating thefagot to a welding and rolling temperature rolling the fagot through aseriesof polygo- ;nal passes to the desired dimensions; and removing therefractory core by advancing compressed air into the hollow bar througha tube at the same time changing the relative positions of the bar andtube ,abouttheir axes.

2." The method of making hollow metal bars, which comprises bundlingweldable rolling the fagot to th e desired dimensionsy and removing therefractory core by advancing compressed air into the hollow bar througha tube at the sametime changing the relative positions of the bar andtube about the r axes, I

.rods' around a hollow core also of weldable 3. The method of makinghollow metal metal to form a fagot; packing the hollow core withgranulated refractory material; heating the fagot to a weldingtemperature; rolling the fagot to the desired dimensions; and removingthe refractory core by advancing compressed air into the hollow barthrough a tube, at the same time revolving the bar. i A

4. The method of making hollow metal bars; which comprises bundlingweldable metal around a hollow core also of weldable metal to form afagot; packing the hollow core with refractory material having a fusingpoint higher than the welding temperature of the core; heating the fagotto a weld ing and rolling temperature; rolling the fagot through aseries. of polygonal passes to the desired dimensions; and removing therefractory core by advancing compressed air into the hollow bar througha tube at the same time changing the relative positions of the bar andtube about their axes.

5. The method ofmaking hollow metal bars, which comprises bundlingweldable metal around a hollow core also of weldable metal to form afagot; packing the hollow core with refractory material having a fusingpoint higher than the welding temperature of the core; heating the fagotto awelding and --rolling temperature; rolling the fagot through aseries of polygonal passes to the desired dimensions; and removing therefractory core by advancing compressed air into the hollow bar througha tube, at

the same time revolving the bar.

' 6. The method of making hollow metal bars, which comprises bundlingweldable metal around a hollow corealso of weldable metal to form afagot; packing the hollow core with refractorymaterial having a fusingpoint higher than the welding temperature of the core; heating the fagotto a welding and rolling temperature; rolling the tag 0t through aseries of polygonal passes to prevent distortion and through a circularpass to the final desired dimensions; and removing the refractory core.

7. The method of making hollow metal bars, which comprises bundlingweldable metal around a hollow core also of weldable metal to form afagot; packing the hollow core with refractory material havinga fusingpoint higher than the welding temperature of the core; heating the fagotto a weld ing and rolling temperature; rolling the fagot through aseries of polygonal passes to prevent distortion and'through a passboundj In testimony whereof I ed by one line to the final desireddimensions; and removing the refractory core.

8. The method of making hollow metal bars, which comprises bundlingweldable metal around a hollow core also of weldable metal to form afagot; packing the hollow core with refractory material having a fusingpoint higher than the welding temperature of the core; heating the fagotto a welding and rolling temperature; rolling the fag- 0t through aseries of polygonal passes to prevent distortion, the sides of the barbeing presented parallel to the sides of the passes; and removing therefractory core by advancing compressed air into the hollow bar througha tube, at the same time revolving the bar. v

9. The method of making hollow metal bars, which comprises bundlingweldable metal around ahollow core also of weldable metal to form afagot; packing the hollow core with refractory material having a fusingpoint higher than the welding temperature of the core; heating the fagotto a welding and rolling temperature; rolling. the fagot to the desireddimensions; and removing the refractory core by advancing compressed airinto the hollow bar through a tube at the same time changing therelative positions of the bar and tube about their axis.

10. The method of making hollow metal bars, which comprises bundlingweldable meta] around a hollow core also of weldable metal to form afagot; packing the hollow core with refractory material having a fusingpoint higher than the welding temperw ture of the core heating the fagotto a welding and rolling temperature; rolling the fagot to the desireddimensions; and removing the refractory core by advancing compressed airinto the hollow bar through a tube, at the same time revolving the bar.

- .11. The method of making hollow metal bars, which comprises bundlingweldable rods around a hollow corealso of weldable metal to form afagot; packing the hollow core with refractory material having a fusingpoint higher than the welding temperature of the core; heating the fagotto a welding and rolling temperature; rolling the fagot through a seriesof polygonal passes and a circular pass to the desired dimensions; andremoving the refractory core by advancing compressed air into the hollowbar through a tube,

fixed my signature.

THOMAS s. VVI-IEELWRIGHT.

have hereunto af-

